The present invention relates to a wood pulp grinder designed for maintaining pressure upon the wood in the grinder during loading of additional wood for being ground, and particularly to an arrangement including a plurality of independently operable press rams in the grinder housing for accomplishing that purpose.
Such a wood pulp grinder is known from German Pat. No. 297,810. In that wood pulp grinder, there are two parallel press rams, each guided in a respective pressing chamber. Those chambers also serve as loading chambers for the wood bolts, in order to feed them to the common grinder magazine. These press rams are acted on alternately by pressure. As a result of the propagation of the pressure in the pile of wood which is present in the press magazine and forms a heap, the pressure is propagated from bolt to bolt of wood to the surface of the grindstone.
In this connection, the press rams are withdrawn into the upper pressing position for the loading of the wood. After lowering of the other press ram upon its work stroke, the work stroke of the press ram which is associated with the individual magazine which has just been loaded is introduced. It is advisable to charge each individual magazine of the individual press rams in the direction parallel to the axial direction of the grindstone. Otherwise, dependable loading of the individual magazines would not be possible. The spacing near the grindstone of the lower edge of the central wall of the press magazines which is arranged between those magazines, i.e. which lower edge is also the bottom end of the stroke of the press rams, is, of course, to be so selected here that, corresponding to the angle of slope for the course of the pressure, the grinding pressure, exerted by a press ram can also spread out over the entire width of the press magazine in the region of the surface of the grindstone.
This arrangement has the disadvantage that the two individual magazines associated with the two respective individual press rams must be charged individually with the wooden bolts so that a separate respective charging apparatus is necessary for both of them. Furthermore, in order to assure the full pressing pressure and its uniformity upon each work stroke, closure plates must be provided in the region close to the grindstone on the individual magazine associated with each individual press ram. These are not mentioned in the patent.